Machines for making tubes, laminated rods, and laminated strips from liquid multicomponent plastic material

ABSTRACT

A machine for making tubes, pipes, laminated rods, and laminated strips from liquid multicomponent plastic material comprises two endless traveling moulding belts between which the plastic material is introduced while in a viscous or pastelike state through a nozzle while a core material and if desired outer layer material are simultaneously introduced between the belts. The core material may be a hose, means being provided for feeding a fluid under pressure to the hose to blow it up into tubular shape, means being provided for removing the hose from the tube when being formed. Alternatively, the nozzle may form the end of a mandrel which carries one or two lengths of hose, a pulsating fluid being supplied to the hose or hoses to inflate and deflate the same, the mandrel reciprocating in synchronism with the pulsations of the fluid. If two hoses are provided, one hose may be mounted on a tubular member reciprocatably mounted on the mandrel, movements of the mandrel and the tubular member being in counterphase to one another.

ts it U ite [ii [54] MACHINES FOR MAKWG TUBES, LAMINATED RODS, ANDLAMINATED STRlllPS FROM LIQUID MULTICOMPONlENT [PLASTIC MATERIAL ll 1Cllalms, 8 Drawing Figs.

[52] ILLS. C1 1W4 ll 264/172 [51] lint. Cl 182% 15/00 [50] Field ofSearch 264/172;

[ 56] Reierences Cited UNITED STATES PATENTS 2,287,830 6/1942Postlewaite 18/4 8 X 3,303,529 2/1967 Boggs 18/4 S [111 anoint AssistantExaminer-L. R. Frye Attorney -Nolte and Nolte ABSTRACT: A machine formaking tubes, pipes, laminated rods, and laminated strips from liquidmulticomponent plastic material comprises two endless traveling mouldingbelts between which the plastic material is introduced while in aviscous or pastelike state through a nozzle while a core material and ifdesired outer layer material are simultaneously introduced between thebelts. The core material may be a hose, means being provided for feedinga fluid under pressure to the hose to blow it up into tubular shape,means being provided for removing the hose from the tube when beingformed. Alternatively, the nozzle may form the end of a mandrel whichcarries one or two lengths of hose, a pulsating fluid being supplied tothe hose or hoses to inflate and deflate the same, the mandrelreciprocating in synchronism with the pulsations of the fluid. if twohoses are provided, one hose may be mounted on a tubular memberreciprocatably mounted on the mandrel, movements of the mandrel and thetubular member being in counterphase to one another PATENTEU M1831 I9713.601, 848

SHEET 1 OF 5 FIG. 7.

4 107619 20 -'-2b 5a 7a 5a 7 ()an 711 6bL 14 INVEINTOR RICHARD ZIPPELATTO RN YS PATENTEU M1631 I97l SHEET 2 [IF 5 FIGS.

INVENTOR RICHARD ZIPPEL Q/Mf 52w; ATTORNE S MACHINES FOR MAKING'IIJDIES, LAMINATED RODEI, AND LAMINATED STRIF FROM lLIQlUIDMUI'I'ICOMFDNIEN'I PLASTIC MAL BACKGROUND OF THE INVENTION The inventionrelates to a machine for making tubes, pipes, laminated rods, andlaminated strips from liquid multicomponent plastic material, themachine comprising two endless moulding belts, the multicomponentplastic material being fed through a nozzle between the moulding belts.

It is known that thermoplastic materials are mouldable into rods andtubes on extruders. However, difficulties are encountered with liquidmulticomponent plastic materials which harden after mixing thecomponents together. For the production of moulded sections from liquidmulticomponent plastic material, which has been mixed in a mixingchamber, it has previously been proposed to force the multicomponentplastic material from the mixing chamber into moulds, which are closedwhen charged, each mould having two parts, one part being fixed to theupper run of an endless conveyor belt and the other part being fixed tothe parallel lower run of a second endless conveyor belt. Alternatively,when the endless conveyor belts are made of silicone rubber,polyethylene or the like and are suitably shaped, they themselves mayserve as a mould. Such conveyor belts facilitate the production andoperation of the moulding machine. The advantage of using multicomponentplastic materials is that the resultant tubes, rods and the like areless aifected by heat than tubes, rods and the like made fromthermoplastic materials, that the tubes, rods and the like may beprovided with transverse ribs and other patterns and that they can bemade of foamed plastic materials, which may be hard foamed or softfoamed plastic material. I-Iard foamed plastic material may be used, forexample, for making rods, while soft foamed plastic material may beused, for example, for making yieldable strips.

However, with the previously proposed machines it has not been possibleto produce tubes, laminated rods and the like and to laminate sucharticles during the production thereof.

It is an object of the present invention to provide a moulding machinefor making tubes, pipes, rods, and strips from multicomponent plasticmaterial, which articles are laminated by moulding on to them or intothem strips of textile fabrics, of plastic material, of glass fibers orthe like.

Of particular importance is the production of tubes from foamedmulticomponent plastic material since such tubes or pipes are of heatinsulating qualities and therefore suitable for carrying hot fluids.Furthermore, such tubes may be used as surgical drain tubes.

Accordingly it is another object of the invention to provide a mouldingmachine for making tubes and pipes from multicomponent plastic materialwhich is foamed.

SUMMARY OF THE INVENTION.

The invention consists in a machine for making tubes, pipes,

laminated rods, and laminated strips from liquid multicomponent plasticmaterial, comprising two endless moulding belts, means including anozzle for feeding the multicomponent plastic material through thenozzle between the moulding belts, means for feeding a tube or stripmaterial between the moulding belts, and means for controlling the flowof the multicomponent plastic material in such a way that it arrivesbetween the moulding belts as a paste.

Means may be provided for feeding a tubing of polyethylene between themoulding belts, there being provided means for feeding into the tubing afluid under pressure, and means for removing the fluid from the tubingwhen the multicomponent plastic material has set.

Other features of the invention will become apparent from the followingdetailed description of three preferred embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS.

To make the invention clearly understood reference will now be made tothe accompanying diagrammatic drawings, which are given by way ofexample and in which:

FIG. I illustrates a first embodiment of a moulding machine of theinvention;

FIG. 2 is a section through a part of the machine of F I6. I on a largerscale;

FIG. 3 is a section along the line III-Ill of FIG. 2;

FIG. 4 illustrates a second embodiment of a moulding machine of theinvention;

FIG. 5 illustrates a part of the machine of FIG. d on a larger scale andpartly in section;

FIG. 6 is a section through a tube being produced by the machine ofFIGS. 4 and 5';

FIG. 7 illustrates a third embodiment of a moulding machine of theinvention; and

FIG. b is a section through a part of the machine of FIG. 7 on a largerscale.

DESCRIPTION OF THE PREFERRED EMBODIMENTS.

The machine of FIGS. 1, 2 and 3 comprises two containers Ia and Ib forstoring the components of a liquid multicomponent plastic material whichare fed by flow metering pumps 2a and 2b into a mixing chamber 3provided with a stirring device 41. The multicomponent plastic materialflows from the mixing chamber 3 through a feed pipe 5 to a nozzle 3(FIG. 2) between endless moulding belts 7a and 7b, which travel rounddriving and guiding rollers 6a, 6a, 6b and 6b. Heaters 9 are fittedadjacent the feed pipe 5 to heat material therein.

Strips 16, 17 of textile fabric, plastic material or glass fibers, whichit is desired to bond to a body 13, which is being produced, aresupplied from storage rolls III and II. From a further storage roll I4runs a flat: tubing 18 which is introduced into the body I3 ofmulticomponent plastic material while it is being formed. The tubing 18forms a lining on the hollow interior walls of the body I3. The tubingI8 drawn from the further storage roll M travels through a central slotId (FIG. 2) in the nozzle II and is thereby positioned centrally withinthe body I3. The strips l6 and 17 are drawn from the storage rolls It)and Ill and the tubing 18 is drawn from the further storage roll 14 bythe force exerted by the two endless moulding belts 7a and 7b. Aseparate drive is thus not required, since the plastic material of thebody 13, as it sets and becomes rigid, automatically draws the strips116, I7 and the tubing lb from the respective storage rolls It), Ill, M.However, brakes I9 for the strips I6, I7 and the tubing Id andadditional rollers 20 positioned obliquely to the direction of travel ofthe strips 16, I7 are provided for straightening the strips I6, I7 andthe tubing 18.

When the moulded body I3 emerges from the moulding machine, the strips16 and I7 are bonded firmly to the outside of the body 13, the tubinglib being firmly bonded to the interior walls of the body I3, (FIG. 3).When a foaming multicomponent plastic material is used, the tubing IIImay be made of thin material which is fed into the moulding machine inthe shape of a strip having two superposed layers. When the body 113 isin use, it assumes a tubular shape when a fluid is fed to the interiorof the tubing III within the body I3.

Alternatively, a tubing which is circular or angular in cross sectionmay be introduced through a ring-shaped nozzle into the body 113 whilebeing produced. The strips Id, I7 form outer coverings and may be of ahard. multicomponent plastic material. Such tubes are usable for a widerange of technological purposes. When the multicomponent plasticmaterial of the body I3 is foamed, such pipes or tubes have excellentheat-insulating properties.

The machine just described ensures that the multicomponent plasticmaterial has already started to set, when the strips I6, I7 and thetubing III are bonded to the plastic material. It is thereby possible toproduce a reliable bond between the main body 13 of multicomponentplastic material and the strips 16, 17 and tubing 18.

By suitably adjusting the heating effect of the heaters 9 and the lengthof the feedpipe 5 the originally liquid multicomponent plastic materialis caused to emerge from the nozzle 8 as a paste or a liquid of highviscosity. This ensures that the tubing 18 stays in the positionrelative to the main part of the body 13 in which it is introduced, themulticomponent plastic material being of such a consistency that thetubing 18 can not substantially change its position during the finalsetting of the multicomponent plastic material. It should be noted thatin most cases, the final setting takes place rapidly once the materialhas started to assume its pastelike consistency.

The mechanical means whereby the material in strip form is introducedwithout folds and wrinkles comprises at least one storage roll or 11, abrake l9 acting on the strip and guide rollers 20. In many cases, it isof advantage to fit a pair of rollers 20, one at each side of the strip,the rollers being positioned obliquely in relation to the direction oftravel of the respective strip. Such rollers pull the strip smooth andtaut.

Within the feed pipe 5 a preliminary reaction between the components maytake place which is followed by setting, or thereaction may include theinitial stage of setting, in which the multicomponent plastic materialchanges from the fluid state either to a condition in which it willshortly become pastelike or to the pastelike condition itself. Theviscosity of the plastic material leaving the nozzle 8 can be varied byvarying the feed rate, which should be matched to the travelling speedof the moulding belts 7a, 7b. The viscosity of the material can also bechanged by altering the length of the feed pipe 5, but the simplest wayof varying the viscosity of the multicomponent plastic material leavingthe nozzle 8 is by suitably varying the heating effect of the heaters 9on the material while it is in the feed pipe 5.

in FIGS. 4, 5 and 6 the same reference numbers but increased by 100"indicate parts similar to those of FIGS. 1, 2 and 3.

The machine of FIGS. 4, 5 and 6 comprises two containers 101a and 101bin which the components of a multicomponent plastic material are stored,which are fed by flow metering pumps 102a and 102b into a mixing chamber103 provided with a stirring device 104. The multicomponent plasticmaterial flows from the mixing chamber 103 through a feedpipe 105 andbetween endless moulding belts 107a and l07b which travel round thedriving and guiding rollers 106a, 106a, 1061) lies beyond the mandrel128. Some of the compressed air escapes past the ring 130a and, withinthe space between the two rings 130a and 130b, passes into a furtherpassage 132, through which the escaping compressed air is dischargedinto the atmosphere. The mandrel 128 is held by a stand 133 fixed to theframe of the machine. On its end adjacent the stand 133, the mandrel 128carries a sufficient supply 131a of polyethylene hose 131 for theproduction of tubes 138 each of 10 meter to 20 meter lengths. FIG. 5shows how the mandrel 128 extends between the moulding belts 107a 107b.Spring means 134 are provided for the polyethylene hose 131 to be kepttaut and for only as much to be drawn from the supply 131a and allowedto pass between the moulding belts 107a and 107!) as is required toenable the polyethylene hose 131 to travel along with the belts 107a,10% without forming folds or wrinkles.

. A thread 135 (FIG. 6) is connected to the end 13lb of the hose 131remote from the stand 133 to serve as a means for extracting thepolyethylene hose 131 from the tube of multicomponent plastic materialwhich is being produced by drawing the thread 135 in the direction ofthe arrow 139. During extraction the polyethylene tubing 131 is detachedat the region 136, where it is folded back, from the tube 138. As willbe obvious, the leading portion 137 of the tube 138 is cut offapproximately along the line AA. The cutoff portion 137 of the tube 138is closed at one end toensure that the polyethylene hose 131 is firmlyattached to the tube 138 at the leading end 137 thereof.

In FIGS. 7 and 8 the same reference numbers but increased by 200indicate parts similar to those of FIGS. 1, 2 and 3.

The multicomponent plastic material is produced and fed in the machinesof FIGS. 7 and 8 in the same manner in the machine of FIGS. 4, 5 and 6.Extending between the endless moulding belts 207a and 207b is a mandrel228 (FIG. 8) which has an internal passage 229 for compressed air toenable the production of pipes and tubes. The compressed-air passage 229opens into a length of polyethylene hose 231 which hose is acted upon bya pulsating supply of fluid under pressure. The mandrel 228 is fitted insuch a way that it reciprocates in the axial direction as indicated bythe double arrows 241 in synchronism with the pulsating pressure fluid.For this purpose the mandrel 228 is mounted in bearings of areciprocatable drive mechanism 251 (FIG. 7). This drive mechanism 251comprises a pressure-fluid cylinder housing a piston reciprocating insynchronism with the pressure fluid acting on the length of the hose231. Reciprocating cylinder piston arrangements are well known in theart and therefore not described in detail.

A tubular member 253 forms a sliding fit on the mandrel 228. Motion isimparted to the tubular member 253 by a second drive mechanism'254 inthe form of a pressure-fluid cylinder and piston arrangement so that thetubular member 253 reciprocates in counterphase to the mandrel 228 asindicated by the double arrows 242. The tubular member 253 carries alength of hose 255 of polyethylene, which is acted upon by a pulsatingpressure fluid supplied through a passage 256. This pulsating pressurefluid acts upon the length of hose 255 on the tubular member 253 incounterphase to the pulsating pressure fluid supplied through thepressure-fluid passage 229 which acts on the length of hose 231 on themandrel 228. The direction of movement of the moulding belts 207a, 2071;is indicated in FIG. 8 by arrows 243.

As is known, polyethylene does not stick and is so smooth that noadhesive and no foamed multicomponent plastic material normally adheresfirmly to it. By the introduction of a hose 131 of polyethylene betweenthe moulding belts 1070, 107b, and by introducing a fluid under pressurewhich may be a liquid or a gas and then relieving the pressure, a pipeor tube can be produced from the multicomponent plastic material. Bypulling the polyethylene hose 131 out of the hardened multicomponentfoamed plastic pipe or tube 138, after the removal of the pressurefluid, by means of the thread 135 it can be ensured that thepolyethylene hose 131 is detached only gradually. The polyethylene hose131 is a thin hose.

It is the mandrel 128 which forms and determines the hollow interior ofthe pipe or tube 138 which is being produced.

By all this it is made possible to produce pipes and tubes of finitelengths up to a maximum of 10 to 20 meters. The length limitation isimposed by the limited length of the polyethylene hose which can beaccommodated on the mandrel.

However, the embodiment of FIGS. 7 and 8 enables pipes and tubes of anydesired length to be made from multicomponent plastic material.

This is due to the provision of the mandrel 228 extending into the spacebetween the two moulding belts 207a, 207b, the mandrel 228 passingthrough the ring-shaped nozzle 208 (FIG. 8) for the multicomponentplastic material, the mandrel carrying at least one length ofpolyethylene hose 231 into which a pressure-fluid passage 229 within themandrel 228 leads from a pulsating pressure source, the mandrel 228being able to move axially and being connected to the reciprocatingdrive mechanism 251 synchronized with the pulsations of the pressurefluid. When the hose is inflated, the drive mechanism 251 moves themandrel 228 approximately in unison with the moulding belts 207a, 207b.

The way in which a tube or pipe is produced in the machine of the thirdembodiment is that the multicomponent plastic material, already in arapidly thickening condition and assuming a pastelilte consistency,emerges from the ring-shaped nozzle 208 and is continuously forcedbetween the moulding belts 207a, 207b by the polyethylene hose on themandrel. Since polyethylene is so smooth that it does not stick, it isensured that the hose separates from the foamed plastic material eachtime a compression of the pressure fluid in the hose is followed by areduction of the pressure, whereupon the hose can be withdrawn, thenreinflated and expanded and is thus caused to move in unison with themoulding belts carrying the multicomponent plastic material with it.This produces a tube or pipe, the cross section of which can be varied,as desired, depending on the shape of the mandrel and of the hose used.

The mode of operation of this machine is improved in the embodiment ofFIGS. 7 and E by fitting the mandrel 228 with the tubular member 253carrying a second length of polyethylene hose 255 and having theinternal pressure-fluid passage 256, the tubular member 253 beingarranged to reciprocate on the mandrel 228 under the action of thereciprocating drive 254 which moves it in counterphase to the motion ofthe mandrel 228. The advantage of this embodiment is that the hose 231on the mandrel 228 can easily be detached and withdrawn while the hose225 on the tubular member 253 is forcing the multicomponent plasticmaterial against the moulding belts 207a, 2417b and thus holding itsteady. This procedure takes place in'reverse when the hose 255 on thetubular member 253 is being detached while the hose 231 on the mandrel228 is acted upon by the fluid under pressure.

I claim:

1. A moulding for producing moulded articles from settable plasticsmaterial comprising in combination:

a feed pipe to receive settable plastics material;

heating means to heat said plastics material to a pastelike consistencywhilst said plastics material is in transit in said feed pipe;

two endless travelling mould means cooperating along portions of theirrespective paths to define a continuous mould cavity;

a nozzle having a duct communicating with said feed pipe to eject saidplastics material into said mould cavity;

said duct encompassing a central passage in said nozzle and having anexternal wall in close proximity to said mould means;

said nozzle projecting between said two endless mould means into saidmould cavity defined therebetween and having an exit orifice within saidcavity; and

guide means to guide elongate material along a path extending in saidcentral passage and said mould cavity.

2. A moulding machine as defined in claim 11, comprising further guidemeans to guide strip material through respective further passagesbetween said outer wall of said duct and the respective ones of said twoendless mould means and into said mould cavity.

3. A moulding machine as defined in claim ll, wherein said elongatematerial comprises inflatable tubular material guided through saidcentral passage and into said mould cavity, whereby said inflatablematerial when within the moulded article may be inflated.

d. A moulding machine as defined in claim 3, wherein said centralpassage comprises a slot of substantially rectangular cross section.

5 A moulding machine as defined in claim ll, further comprising amandrel extending through said central passage and projecting therefrominto said mould cavity, a shroud of said elongate material shrouding anend portion of said mandrel in said mould cavity and extending throughsaid central passage, said mandrel having at least a first internalpassage to supply fiuid under pressure to the interior of said shroud,and said guide means comprising a gap defined between the outer surfaceof said mandrel and said internal wall of said duct for the introductionof said shroud into said cavity.

6. A moulding machine as defined m 0 arm 5, wherein said central passageis substantially circular in cross section, said mandrel issubstantially cylindrical and said gap is annular, and said elongatematerial comprises a polyethylene hose.

7. A moulding machine as defined in claim 6, wherein said end portion ofsaid mandrel is provided with two protruding annular ribs which arespaced a predetermined distance apart along the axis of said mandrel,and said mandrel is provided with a second fluid passage terminatingbetween said annular ribs and communicating with the atmosphere.

8. A moulding machine as defined in claim 1, further comprising amandrel extending through said central passage and projecting therefrominto said mould cavity, an envelope of said elongate material shroudingan end portion of said mandrel inside said mould cavity, and means forreciprocating said mandrel to guide said envelope of elongate materialalong a path extending into said central passage and said mould cavity,said mandrel having an internal passage to supply a fluid underpulsating pressure to said envelope, and means to reciprocate saidmandrel in synchronism with said pulsations.

9. A moulding machine as defined in claim 9, wherein said elongatematerial comprises a polyethylene hose.

110. A moulding machine as defined in claim ll, further comprising amandrel extending through said central passage and projecting therefrominto said mould cavity, a first envelope of said elongate materialshrouding an end portion of said mandrel inside said mould cavity, meansfor reciprocating said mandrel to guide said first envelope of elongatematerial along a path extending in said cavity, a tubular memberslidably mounted on an intermediate portion of said mandrel, a furtherenvelope of said elongate material mounted on said tubular member, saidmandrel having an internal passage to supply fluid under pulsatingpressure to said first envelope, said tubu lar member having an internalpassage: to supply fluid under pulsating pressure to said furtherenvelope, and means to reciprocate said mandrel in synchronism with saidpulsations of said fluid supplied to said first envelope, further meansto reciprocate said tubular member relative to said mandrel to guidesaid further envelope of said elongate material along a path extendinginto said central passage and said mould cavity, and means to coordinatesaid reciprocal movement of said tubular member in counterphase to saidreciprocal movement of said mandrel.

llll. A moulding machine as defined in claim 10, wherein said elongatematerial comprises a polyethylene hose.

1. A moulding for producing moulded articles from settable plasticsmaterial comprising in combination: a feed pipe to receive settableplastics materIal; heating means to heat said plastics material to apastelike consistency whilst said plastics material is in transit insaid feed pipe; two endless travelling mould means cooperating alongportions of their respective paths to define a continuous mould cavity;a nozzle having a duct communicating with said feed pipe to eject saidplastics material into said mould cavity; said duct encompassing acentral passage in said nozzle and having an external wall in closeproximity to said mould means; said nozzle projecting between said twoendless mould means into said mould cavity defined therebetween andhaving an exit orifice within said cavity; and guide means to guideelongate material along a path extending in said central passage andsaid mould cavity.
 2. A moulding machine as defined in claim 1,comprising further guide means to guide strip material throughrespective further passages between said outer wall of said duct and therespective ones of said two endless mould means and into said mouldcavity.
 3. A moulding machine as defined in claim 1, wherein saidelongate material comprises inflatable tubular material guided throughsaid central passage and into said mould cavity, whereby said inflatablematerial when within the moulded article may be inflated.
 4. A mouldingmachine as defined in claim 3, wherein said central passage comprises aslot of substantially rectangular cross section. 5 A moulding machine asdefined in claim 1, further comprising a mandrel extending through saidcentral passage and projecting therefrom into said mould cavity, ashroud of said elongate material shrouding an end portion of saidmandrel in said mould cavity and extending through said central passage,said mandrel having at least a first internal passage to supply fluidunder pressure to the interior of said shroud, and said guide meanscomprising a gap defined between the outer surface of said mandrel andsaid internal wall of said duct for the introduction of said shroud intosaid cavity.
 6. A moulding machine as defined in claim 5, wherein saidcentral passage is substantially circular in cross section, said mandrelis substantially cylindrical and said gap is annular, and said elongatematerial comprises a polyethylene hose.
 7. A moulding machine as definedin claim 6, wherein said end portion of said mandrel is provided withtwo protruding annular ribs which are spaced a predetermined distanceapart along the axis of said mandrel, and said mandrel is provided witha second fluid passage terminating between said annular ribs andcommunicating with the atmosphere.
 8. A moulding machine as defined inclaim 1, further comprising a mandrel extending through said centralpassage and projecting therefrom into said mould cavity, an envelope ofsaid elongate material shrouding an end portion of said mandrel insidesaid mould cavity, and means for reciprocating said mandrel to guidesaid envelope of elongate material along a path extending into saidcentral passage and said mould cavity, said mandrel having an internalpassage to supply a fluid under pulsating pressure to said envelope, andmeans to reciprocate said mandrel in synchronism with said pulsations.9. A moulding machine as defined in claim 8, wherein said elongatematerial comprises a polyethylene hose.
 10. A moulding machine asdefined in claim 1, further comprising a mandrel extending through saidcentral passage and projecting therefrom into said mould cavity, a firstenvelope of said elongate material shrouding an end portion of saidmandrel inside said mould cavity, means for reciprocating said mandrelto guide said first envelope of elongate material along a path extendingin said cavity, a tubular member slidably mounted on an intermediateportion of said mandrel, a further envelope of said elongate materialmounted on said tubular member, said mandrel having an internal passageto supply fluid under pulsating pressure to said first envelope, saidtubular member having an Internal passage to supply fluid underpulsating pressure to said further envelope, and means to reciprocatesaid mandrel in synchronism with said pulsations of said fluid suppliedto said first envelope, further means to reciprocate said tubular memberrelative to said mandrel to guide said further envelope of said elongatematerial along a path extending into said central passage and said mouldcavity, and means to coordinate said reciprocal movement of said tubularmember in counterphase to said reciprocal movement of said mandrel. 11.A moulding machine as defined in claim 10, wherein said elongatematerial comprises a polyethylene hose.